NetFlow Activation and Deployment Information SonicWALL recommends careful planning of NetFlow deployment with NetFlow services activated on strategically located edge/aggregation routers which capture the data required for planning, monitoring and accounting applications. Key deployment considerations include the following: • Understanding your application-driven data collection requirements: accounting applications may only require originating and terminating router flow information whereas monitoring applications may require a more comprehensive (data intensive) end-to-end view • Understanding the impact of network topology and routing policy on flow collection strategy: for example, avoid collecting duplicate flows by activating NetFlow on key aggregation routers where traffic originates or terminates and not on backbone routers or intermediate routers which would provide duplicate views of the same flow information • NetFlow can be implemented in the SonicOS management interface to understand the number of flow in the network and the impact on the router. NetFlow export can then be setup at a later date to complete the NetFlow deployment. NetFlow is in general an ingress measurement technology which should be deployed on appropriate interfaces on edge/aggregation or WAN access routers to gain a comprehensive view of originating and terminating traffic to meet customer needs for accounting, monitoring or network planning data. The key mechanism for enhancing NetFlow data volume manageability is careful planning of NetFlow deployment. NetFlow can be deployed incrementally (that is, interface by interface) and strategically (that is, on well chosen routers) —instead of widespread deployment of NetFlow on every router in the network.